1p3/2 Proton-Hole State in Sn132 and the Shell Structure Along N =82

A low-lying state in In₈₂131, the one-proton hole nucleus with respect to double magic Sn132, was observed by its γ _{decay to the ^Iπ=1/^2- β-emitting isomer. We identify the new state at an excitation energy of Ex}=1353 keV, which was populated both in the β decay of Cd13183 and after β_{-delayed neutron emission from Cd13284}, as the previously unknown πp_3/2 single-hole state with respect to the Sn132 core. Exploiting this crucial new experimental information, shell-model calculations were performed to study the structure of experimentally inaccessible N =82 isotones below Sn132. The results evidence a surprising absence of proton subshell closures along the chain of N =82 isotones. The consequences of this finding for the evolution of the N =82 shell gap along the r-process path are discussed.